Fluidic die sense architecture

ABSTRACT

A fluidic die includes a sense architecture having a global sense block to provide an analog reference signal and an array of distributed sense blocks. Each distributed sense block is to receive a same set of addresses via an address bus and each is to receive a corresponding sense enable signal having an enable value or a disable value. Each distributed sense block includes an array of sensors, each sensor corresponding to a different address of the set of addresses and a sample circuit to apply the analog reference signal to the sensor corresponding to the address on the address bus when the corresponding sense enable signal has the enable value, and provide to the global sense block an analog sense signal from the sensor resulting from application of the analog reference signal.

BACKGROUND

Fluidic dies may include an array of nozzles, where each nozzle includesa fluid chamber, a nozzle orifice, and a fluid actuator, where the fluidactuators may be actuated to cause displacement of fluid and causeejection of fluid drops from the nozzle orifices to produce an article.Some example fluidic dies may be printheads where the fluid maycorrespond to ink. Fluidic dies may include sensors, or arrays ofsensors, to monitor operation of the fluidic die.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block and schematic diagram of a fluidic die having a sensearchitecture, according to one example.

FIG. 2 is a block and schematic diagram generally illustrating a fluidicejection system including a fluidic die having a sense architecture,according to one example.

FIG. 3 is a block and schematic diagram generally illustrating fluidicdie including sensor architecture, according to one example.

FIG. 4 is a flow diagram generally illustrating a method of operating afluidic die having a plurality of sensors, according to one example ofthe present disclosure.

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown byway of illustration specific examples in which the disclosure may bepracticed. It is to be understood that other examples may be utilizedand structural or logical changes may be made without departing from thescope of the present disclosure. The following detailed description,therefore, is not to be taken in a limiting sense, and the scope of thepresent disclosure is defined by the appended claims. It is to beunderstood that features of the various examples described herein may becombined, in part or whole, with each other, unless specifically notedotherwise.

Fluidic dies may include a number of fluid actuators. The fluidicactuators may include a piezoelectric membrane based actuator, a thermalresistor based actuator, an electrostatic membrane actuator, amechanical/impact driven membrane actuator, a magneto-strictiveactuator, or other suitable element that may cause displacement of fluidin response to electrical actuation. In some examples, a fluid actuatormay be disposed in a nozzle, where in addition to the fluid actuator,the nozzle may comprise a fluid chamber and a nozzle orifice, whereactuation of the fluid actuator displaces fluid in the fluid chamber tocause ejection of a fluid drop from the nozzle orifice. Accordingly, afluid actuator disposed in a nozzle may be referred to as a fluidejector or drop ejector.

In some examples, a fluid actuator may be disposed in fluid channels,chambers, or other suitable structures, which facilitate conveyance offluid within the fluidic die, such as to nozzle fluid chambers, forexample. In such implementations, actuation of a fluid actuator maydisplace and control movement of fluid to desired locations within thefluidic die. Accordingly, a fluid actuator disposed in a fluidic channelor other such structure may be referred to as a fluid pump or simply asa pump.

The plurality of fluid actuators of a fluidic die may be referred to asan array of fluid actuators. In one example, the array of fluidactuators may be arranged in a column. Fluid actuators of the array offluid actuators may be selectively actuated to cause fluid drops to beejected from nozzle orifices to produce an article. In a case where thefluid comprises ink, the fluidic die may be implemented as a printheadwith the article being a printed image. An actuation event, as usedherein, may refer to individual or concurrent actuation fluid actuatorsto cause fluid displacement, including ejection of fluid from a nozzle.

In example fluidic dies, the array of fluid actuators may be arranged insets or groups of fluid actuators, where each set of fluid actuators maybe referred to as a “primitive” or “firing primitive”, where a number offluid actuators in a primitive may be referred to a size of theprimitive. In one example, each primitive has a same set of addresses,with each fluid actuator of a primitive corresponding to a differentaddress of the set of addresses. In some examples, electrical, thermal,and fluid operating constraints of a fluidic die may limit which fluidactuators of each primitive may be concurrently actuated for a givenactuation event. Arranging fluidic actuators into primitives facilitatesaddressing and actuation of subsets of fluid actuators of the array offluid actuators which may be concurrently actuated for a given actuationevent to remain within operating constraints of the fluidic die.

By way of example, consider a fluidic die having four primitives, witheach primitive having eight fluid actuators and a same set of eightaddresses (e.g., 0 to 7), with each fluid actuator corresponding to adifferent address of the set of addresses. In one case, according to oneexample, the fluidic die may have operating constraints that limit thenumber of fluid actuators that may be concurrently actuated for a givenactuation event to one fluid actuator per primitive, for example. Insuch case, for a first actuation event, the fluid actuator correspondingto address “0” of each primitive may be actuated, followed by a secondactuation event, where the fluid actuator corresponding to the address“1” of each primitive may be actuated, and so on, until the fluidactuators at each address of each primitive may have been actuated. Itis noted that such example is provided for illustrative purposes onlyand that any number of other implementations are possible.

Example fluidic dies may include sensors, or arrays of sensors, tomonitor operation of the fluidic die. For instance, thermal sensors maybe disposed on the fluidic die to monitor operating temperatures of thefluidic die to ensure that the fluidic die operates within thermaloperating constraints of the die. In another instance, each nozzle mayinclude an integrated drive bubble detect (DBD) sensor to measure animpedance through the fluid chamber of the nozzle during actuation ofthe fluid actuator to determine an operation condition of the nozzle(e.g., whether the nozzle is operating properly or whether the nozzle isblocked or partially blocked).

In some examples, to operate each sensor, a reference circuit generatesa reference signal (e.g., a voltage signal or a current signal). Sampleand sense circuitry associated with the sensor selectively provides thereference to the sensor and samples (measures) an analog sense signalgenerated by the sensor in response to the reference signal. In someexamples, the analog sense signal may be converted on-die to a digitalsense signal by an associated A/D converter.

Circuitry is most dense in a nozzle region of a fluidic die. While asensor requires a relatively small amount circuit area and is capable ofbeing replicated many times on a fluidic die (e.g., thousands of times),sense architecture, including sample and sense circuitry, A/Dconverters, and especially reference circuitry to generate analogreference signals, require larger amounts of circuit area, therebylimiting a number of sensors that may be disposed on a fluidic die ifreplicated for each sensor.

FIG. 1 is a block and schematic diagram of a fluidic die 20, accordingto one example of the present disclosure, having a sense architecture 30including plurality of sensors which share global reference circuitryand which is arranged arrays of sensors, where each array of sensorsshares corresponding sample circuitry. As will be described in greaterdetail below, by sharing global reference circuitry and sample circuitrywith multiple sensors, sense architecture 30, in accordance with thepresent disclosure, efficiently utilizes circuit area on fluidic die 20to enable the implementation of a large number of sensors (e.g.,thousands of sensors) on fluidic die 20.

According to one example, sensor architecture 30 includes a global senseblock 32 and an array 34 of distributed sense blocks (DSBs), indicatedas DSB-1 to DSB-M, with each DSB including a sample circuit 36 and anarray 38 of sensors 40. According to one example, each DSB receives asame set of address, A1 to AN, such as via an address bus 50, with eachsensor 40 corresponding to a different address of the set of addresses,indicated as A1 to AN.

Each DSB further receives a corresponding enable signal via a set ofenable lines 52, indicated as enable signals EN-1 to EN-M, with eachenable signal having an enable value or a disable value. According toone example, an enable signal 52 having an enable value activates thecorresponding DSB to perform sensing operations, while an enable signalhaving a disables the corresponding DSB. In one example, only one enablesignal 52 may have an enable value an enable value at a time so thatonly one DSB is activated to perform sensing operations at a given time.In one example, address and enable signal are generated on fluidic die20 (not illustrated). In one example, address and enable signals arereceived from an external die controller (not illustrated). In oneexample, address and enable signals may be provided by on-die addressand enable signal controllers (not illustrated).

In one example, global sense block 32 provides an analog referencesignal to each DSB, such as via a bus 60, where such analog referencesignal may be an analog voltage reference signal or an analog currentreference signal, for instance. According to one example, the samplecircuit 36 of the DSB corresponding to the enable signal 52 having anenable value provides the analog reference signal from bus 60 to thesensor 40 corresponding to the address on address bus 50 (e.g., addressA0 to AN), and provides an analog sense signal generated by the sensor40 in response to analog reference signal to global sense block 32, suchas via a bus 62.

In one instance, for example, each of the sensors 40 may comprise athermal sensor which, in response to application of an analog referencecurrent signal, generates an analog voltage sense signal which isindicative of a temperature of fluidic die 20 at a location at which thesensor 40 is disposed. In another instance, for example, each sensor maycomprise a drive bubble detect (DBD) sensor corresponding to a nozzle onfluidic die 20 (not shown) which, in response to application of ananalog reference current signal, generates an analog voltage sensesignal which is indicative of an operating condition of thecorresponding nozzle.

In one example, global sense block may include an A/D converter 70 toconvert the analog sense signal received via bus 62 to a digital sensesignal, and provides the digital sense signal via a bus 72, such as toan external die controller, or example. In one instance, the analogreference signal provided by global sense block 32 and the resultinganalog sense signal provided from the DSBs to the global sense block 32may use a same bus (e.g., bus 60) and be temporally controlled.

By employing an array of distributed sense blocks (DSBs) which includean array of sensors sharing sample circuitry, and by sharing a globalreference block generating analog reference signals between the DSBs ofthe array of DSBs, sense architecture 30, in accordance with the presentapplication, efficiently utilizes circuit area on fluidic die 20, andenables the implementation of a large number of sensors (e.g., thousandsof sensors) on fluidic die 20. Additionally, the generation of analogreference signals and analog-to-digital conversion is sensitive toelectrical noise such as that generated by high voltage switching offluid actuators in a nozzle region of fluidic die 20. By consolidatinganalog reference signal generation and A/D conversion in global senseblock 32 and sharing such functions with the array of DSBs, sensearchitecture 30 enables circuitry associated with the generation ofanalog reference signals and A/D conversion to be instantiated fewertimes (e.g., once) on fluidic die 20 and enables such circuitry to bedisposed away from the electrically noisy nozzle region.

FIG. 2 is a block and schematic diagram generally illustrating anexample of a fluidic ejection system 64 including a fluidic diecontroller 66 and a fluidic die 20 having a sense architecture 30 (e.g.,as illustrated by FIG. 1), in accordance with the present application.In one example, fluidic die controller 66 provides address data in theform of the set of addresses A1 to AN and enable signal data in the formof the set of enable signals EN-1 to EN-M (each having an enable valueor a disable value) to input logic 68 of fluidic die 20 via acommunication path 69. According to one example, input logic 68respectively places the address and enable signal values indicated viacommunication path 69 on address bus 50 and enable lines 52.

According to one example, fluidic die controller 66 provides enablesignal data such that only one enable signal of the set of enablesignals EN-1 to EN-M has an enable value (e.g., a value of “1”) at agiven time, so that only one DSB o the array of DSBs is active at agiven time. As described above with respect to FIG. 1, the samplecircuit 36 of the DSB corresponding to the enable signal having theenable value applies the analog reference signal provided by globalsense block via bus 60 to the sensor 40 of the array of sensors 38corresponding to the address A1 to AN on address bus 50. Sample circuit36 samples a resulting analog sense signal generated by thecorresponding sensor 40 in response to application of the analogreference signal, and provides the analog reference signal to globalsense block 32 via bus 62. In one example, global sense block 32 maycommunicate the analog sense signal to fluidic die controller 66 via acommunications path 72. In one example, A/D converter 70 of global senseblock 32 converts the analog sense signal to a digital sense signal andcommunicates the digital sense signal to fluidic die controller 66 viacommunication path 72.

FIG. 3 is a block and schematic diagram generally illustrating fluidicdie 20 including sensor architecture 30 according to one example. In oneexample, in addition to A/D converter 70, global sense block 32 includesa global sense controller 74 and a global reference circuit 76. Inaddition to sample circuit 36 and sensor array 38, each DSB furtherincludes DSB logic 80 and a driver circuit 82, with the DSB logic 80 ofeach DSB receiving the corresponding enable signal (EN-1 to EN-B) andtiming signals from global sense controller 74 via a bus 84.

According to the example of FIG. 3, fluidic die includes a plurality offluid ejection nozzles 90 arranged to form a plurality of primitives,illustrated at primitives P1 to PM, with each primitive including anarray 92 of nozzles 90. According to one example, each primitivereceives the same set of addresses, A1 to AN, via bus 50 as are receivedby each DSB, with each nozzle 90 corresponding to a different one of theaddresses A1 to AN. In example, each primitive, P1 to PM, respectivelyreceives a corresponding fire signal, FS-1 to FS-M, via a set of firesignal lines 94, with each having a fire value or a non-fire value. Whenthe fire signal for a given primitive has a fire value, the nozzle 90corresponding to the address, A1 to AN, on address bus 50 is initiatedto fire so as to eject a fluid drop based on firing data (not shown).

In one example, each DSB corresponds to a different one of theprimitives, with DSB-1 to DSB-M respectively corresponding primitives P1to PM, and with sensors A1 to AN of each sensor array of each DSBrespectively corresponding to nozzles A1 to AN of the correspondingprimitive. For instance, in one example, each sensor A1 to AN of eachprimitive comprises a drive bubble detect (DBD) sensor of thecorresponding nozzle A1 to AN of the corresponding primitive, where anoutgoing signal (e.g., a voltage or current signal) generated by the DBDsensor driven by an analog input signal is indicative of an operatingcondition of the nozzle.

An example of an operation of sense architecture 30 is described below.According to one example, only one enable signal of the set of enablesignals EN-1 to EN-M received via enable lines 52 has an enable value ata given time. For illustrative purposes, consider a scenario whereenable signal EN-1 has an enable value, meaning that only DSB-1 of thearray of DSBs 34 will be activated and be coupled to global sense block32. In one example, upon DSB logic 80 of DSB-1 receiving enable signalEN-1 having an enable value (e.g., a value of “1”), DSB logic 80 updatesthe address provided to the sensor array 38 with the current address onbus 50 and directs sample circuit 36 to receive an analog currentreference signal via bus 60.

According to the illustrated scenario, upon firing signal FR-1 having afiring value (e.g., a value of “1”) so as to cause firing of the nozzle90 corresponding to the address on address bus 50 (e.g., A1 to AN), DSBlogic 80 directs driver circuit 82 to drive the fire signal local toDSB-1 (in this instance, fire signal FR-1) onto bus 62 so as to beemployed as a timing signal by global sense controller 74. In oneexample, driver circuit 82 may include one or more digital tri-statedrivers to drive digital timing signals onto bus 62 and one or moreanalog drivers to drive analog sense signals onto bus 62.

In one example, upon receiving the timing signal via bus 62 from drivercircuit 82, global sense controller 74 provides a sequence of timingsignals to DSB logic 50 via timing bus 84 indicating when DSB logic 50is to instruct sample circuit 36 to apply the analog reference signalfrom global reference circuit 76 to the selected sensor 40 (i.e., thesensor 40 corresponding to the address on address bus 50), when samplecircuit 36 is to sample the resulting analog sense voltage generated bythe selected sensor 40, and when driver circuit 82 is to drive theanalog sense signal onto bus 62. According to one example, global senseblock 32, via A/D converter 70, converts the analog sense signalreceived from driver circuit 82 via bus 62 to digital sense signal 72.In one case, digital sense signal 72 may be conveyed to an off-diecontroller (not illustrated).

In one example, buses 60 and 62 may comprise a single bus, with controlof when analog reference signals from global reference circuit 76 andtiming signals and analog sense signals from driver circuit 82 areplaced on the single bus being controlled by global sense controller 74.

In one example, more than one DSB of the array of DSBs 34 may beactivated via the set of enable lines 52 (i.e., more than one enablesignal EN-1 to EN-M may be have enable value at a given time). Accordingto one example of such a scenario, multiple sets of buses 60, 62, and 84may be employed to communicate between the multiple activated DSBs andglobal sense block 32. In some examples the DSBs of the array of DSBs 34may be grouped into sub-arrays, with one enable signal corresponding toeach sub-array, where one DSB in each sub-array may be activated.

In one example, where sensors 40 are not directly associated with orintegrated with a nozzle 90 (such as is the case with sensors 40 beingDBD sensors), for instance, when sensors 40 comprise thermal sensors,DSB logic 80 of each DSB-1 to DSB-M may not receive a corresponding firesignal FR-1 to FR-M. In such case, initiation of a sensing operation maybe initiated by global sense controller 74 via bus 84.

In one example, global sense block 32 may be used with multiple arrays34 of DSBs (not illustrated). According to such example, each DSB array34 would have a corresponding set of buses 60, 62, and 84 forcommunicating with global sense block 32, where global sense block 32would include multiplexing circuitry to connect with only one set ofbuses of one array 34 of DSBs at a given time. In other embodiments,each DSB array 34 may be in communication with its own correspondingglobal sense block 32 (i.e., one global sense block 32 for each DSBarray 34).

FIG. 4 is a flow diagram generally illustrating a method 120 ofoperating a fluidic die having a plurality of sensors, according to oneexample of the present disclosure, such as fluidic die 20 having aplurality of sensors 40, as illustrated by FIG. 1. At 122, method 120includes arranging the plurality of sensors into a number of sensorarrays, with each sensor array having a corresponding enable signal anda same set of addresses, and each sensor corresponding to a differentaddress of the set of addresses, such as sensors 40 of FIG. 1 beingarranged into a plurality of arrays 38, with each sensor 40 of eacharray 38 corresponding to a different address of the set of addresses A1to AN, and each array 38 having a corresponding enable signal EN-1 toEN-M.

At 124, the method includes providing a global analog reference signalto the sensor arrays, such as a global analog reference signal beingprovided by global sense block 32 to each sensor array 38 via bus 60 inFIG. 1. The method, at 126, further includes providing addresses of theset of addresses on an address bus, such as the set of addresses A1 toAN being provided via address bus 50 to each sensor array 38 in FIG. 1.

At 128, the method includes providing a set of enable signals, eachenable signal corresponding to a different one of the sensor arrays andhaving an enable value or a disable value, such as enable signals EN-1to EN-B respectively corresponding to the sensor arrays 38 of DSBs 1-Mof FIG. 1. At 130, method 120 includes applying the global referencesignal to the sensor corresponding to the address on the address bus ofthe sensor array having a corresponding enable signal with an enablevalue to generate an analog sense signal, such as applying the analogreference signal on bus 60 to the sensor 40 corresponding to the addressA1 to AN on address bus 50 and of the array of sensors 38 of the DSBcorresponding to the enable signal EN-1 to EN-B having an enable value,as illustrated by FIG. 1. In one example, only one enable signal of theset of enable signals has an enable value at a given time.

Although specific examples have been illustrated and described herein, avariety of alternate and/or equivalent implementations may besubstituted for the specific examples shown and described withoutdeparting from the scope of the present disclosure. This application isintended to cover any adaptations or variations of the specific examplesdiscussed herein. Therefore, it is intended that this disclosure belimited only by the claims and the equivalents thereof.

1. A fluidic die comprising: a sense architecture including: a globalsense block to provide an analog reference signal; an array ofdistributed sense blocks, each distributed sense block to receive a sameset of addresses via an address bus and each to receive a differentcorresponding sense enable signal having an enable value or a disablevalue, each distributed sense block including: an array of sensors, eachsensor corresponding to a different address of the set of addresses; anda sample circuit to: apply the analog reference signal to the sensorcorresponding to the address on the address bus when the correspondingsense enable signal has the enable value; and provide to the globalsense block an analog sense signal from the sensor resulting fromapplication of the analog reference signal.
 2. The fluidic die of claim1, the global sense circuit including an analog-to-digital converter toconvert the analog sense signal to a digital sense signal.
 3. Thefluidic die of claim 1, including at least one bus for communicating theanalog reference signal and the analog sense signal between the samplecircuit of each distributed sense block and the global sense block. 4.The fluidic die of claim 1, including a timing bus for communicatingtiming signals from the global sense block to each distributed senseblock.
 5. The fluidic die of claim 1, including the global sense blockproviding one of an analog voltage reference signal and an analogcurrent reference signal.
 6. The fluidic die of claim 1, including aplurality of arrays of distributed sense blocks, the global sense blockincluding multiplexing circuitry to couple only one array of theplurality of arrays of distributed sense blocks to the global senseblock at a time.
 7. A fluidic ejection system comprising: a controllerto provide a set of addresses and a set of sense enable signals, eachsense enable signal having an enable value or a disable value; a fluidicdie including: a sense architecture including: a global sense block toprovide an analog reference signal; and an array of distributed senseblocks, each distributed sense block corresponding to a different enablesignal of the set of enable signals, each distributed sense blockincluding: an array of sensors, each sensor corresponding to a differentaddress of the set of addresses; and a sense circuit to:  apply theanalog reference signal to the sensor corresponding to the address onthe address bus when the corresponding sense enable signal has theenable value; and  provide to the global sense block an analog sensesignal from the sensor resulting from application of the analogreference signal.
 8. The fluidic system of claim 7, including at leastone bus for communicating the analog reference signal and the analogsense signal between each distributed sense block and the global senseblock.
 9. The fluidic system of claim 7, the global sense block toprovide an analog signal comprising one of an analog voltage referencesignal and an analog current reference signal.
 10. A method operating afluidic die having a plurality of sensors comprising: arranging theplurality of sensors into a number of sensor arrays with each sensorhaving a same set of addresses and having corresponding enable signal,with each sensor of each sensor array corresponding to a differentaddress of the set of addresses; providing a global analog referencesignal; providing addresses of the set of addresses on an address bus;providing a set of enable signals, each enable signal corresponding to adifferent one of the sensor arrays and having an enable value or adisable value; and applying the global analog reference signal to thesensor corresponding to the address on the address bus of the array ofsensors having a corresponding enable signal with an enable value togenerate an analog sense signal.
 11. The method of claim 10, includingproviding only one enable signal of the set of enable signal with anenable value at a given time.
 12. The method of claim 10, includingcommunicating the analog reference signal and the analog sense signal atdifferent times on a same bus.
 13. The method of claim 10, includingproviding the analog sense signal to a global analog to digitalconverter to convert the analog sense signal to a digital sense signal.14. The method of claim 10, including providing a global analogreference signal comprising one of a global analog voltage signal and aglobal analog current signal.
 15. The method of claim 10, includingproviding a sample circuit for each sensor array, each sample circuit toapply the global analog reference signal to the sensor of thecorresponding array having the address on the address bus and to samplean analog signal generated by the sensor in response to the applicationof the analog reference signal to provide the analog sense signal.